Obstructive and non-obstructive coronary artery disease in long-lasting type 1 diabetes: a 7-year prospective cohort study

INTRODUCTION It is widely believed that patients with diabetes are at increased risk of severe and premature coronary artery disease (CAD) when compared with nondiabetic individuals. OBJECTIVES The aim of the study was to evaluate the prevalence, 7‑year incidence, predictors, and outcomes of obstructive and nonobstructive CAD in patients with long‑lasting type 1 diabetes. PATIENTS AND METHODS We enrolled 2330 patients at a median age of 50 years and a median diabetes duration of 32 years. All participants underwent diagnostic workup for CAD with an exercise treadmill test (ETT), single‑photon emission computed tomography (SPECT), or both. Coronary angiography was performed in patients with abnormal ETT/SPECT results and repeated during the study if clinically indicated. RESULTS The prevalence of obstructive and nonobstructive CAD was 6.9% and 42%, respectively, while the 7‑year incidence, 1.9% and 7.4%, respectively. Of the 160 revascularized patients, 38% underwent complete revascularization. Acute coronary syndromes were reported in 3.6% of patients (54% with nonobstructive CAD). Cardiac deaths were reported in 1.07% of the population, and only in patients with obstructive CAD. Age, diabetes duration, hypertension, and renal failure were predictors of obstructive CAD, while type 1 diabetes duration, glycated hemoglobin A1c levels, frequent severe hypoglycemia, hypertension, triglyceride levels, renal failure, and cardiac autonomic neuropathy predicted nonobstructive CAD. CONCLUSIONS Nonobstructive CAD was the most frequent coronary complication in patients with type 1 diabetes. Both obstructive and nonobstructive CAD showed a similar incidence of nonfatal outcomes and selected predictors. Positive ETT/SPECT results were related to glycemic control only in patients with nonobstructive CAD.